Cold start
- When all types of warm starts are unsuccessful.
- When you want to change the size of the job control table data
set (JCT), move the JCT to a device of a different device type, or
relocate the JCT to a device of the same device type.
You can avoid a cold start in this case by using the JCT Utility, IATUTJCT, to copy the contents of your old JCT data set to a new JCT data set. See JCT Utility (IATUTJCT) for more information on the JCT Utility. You cannot use any other utility to do this copy because the JCT data set contains information that is dependent on the volume and the location on that volume where the data set resides.
- When you have changed the BUFSIZE parameter on the BUFFER initialization statement.
- When you have changed the SE parameter on the OPTIONS statement.
- When you have changed the STT or STTL parameter on a TRACK or FORMAT statement and want the change to become effective immediately for existing spool data sets.
- When you have changed the sequence of MAINPROC statements. (You can add statements to the end of the sequence or delete statements from the end of the sequence without doing a cold start.).
During a cold start, JES3 reads and processes the initialization stream. JES3 also removes all jobs (jobs that were active and jobs that were in the job queue at the time of the cold start) from the system. Thus, you must resubmit all jobs after a cold start.
All FSSs terminate at IPL time. Any changes to the definition of an FSS brought about by using the *MODIFY operator command before the cold start are lost. To restart a C/I FSS after a cold start, you must have specified START=YES on its FSSDEF statement or you must issue the *MODIFY,F,FSSNAME=fssname,ST=YES operator command.
If JES3 is running properly before the cold start, you can save jobs by using the dump job (DJ) facility and then restore them after the cold start has been performed. This facility is described in z/OS JES3 Commands.
- Hot start (H)
- Hot start with analysis (HA)
- Hot start with refresh (HR)
- Hot start with refresh and analysis (HAR)
- Cold start (C)
- Warm start (W)
- Warm start with analysis (WA)
- Warm start to replace a spool data set (WR)
- Warm start with analysis to replace a spool data set (WAR)
| Characteristics | H | HA | HR | HAR | W | WA | WR | WAR | C |
|---|---|---|---|---|---|---|---|---|---|
| Retains Job Queue | Y | Y | Y | Y | Y | Y | Y | Y | N |
| Read Init. Stream | N | N | Y | Y | Y | Y | Y | Y | Y |
| Spool Data Lost | N | N | N | N | N | N | N | N | Y |
| Replace Spool Data Set | N | N | N | N | N | N | Y | Y | Y |
| Reinstate Spool Data Set | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| Remove Spool Data Set | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| Add Spool Data Set | N | N | N | N | Y | Y | Y | Y | Y |
| IPL Global | O | O | O | O | R | R | R | R | R |
| IPL Locals | O | O | O | O | R | R | R | R | R |
| Job Disposition (see notes) | 1,2 | 1,2,5 | 1,2 | 1,2,5 | 4 | 4,5 | 4 | 4,5 | 3 |
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